Bernd,thanks for the response!
The scanner does have some type of log function that I
need to figure out this week. About the cat,I can say
for sure that it is operational. Don't know about
plugged,but the after cat O2 sensor has very little
fluctuation. When I crack the throttle,I do see a lot
of response out of it for an instant,then it
immediately settles down. Pre-cat sensor fluctuates as
normal.
I have suspected the cat myself,because the Dak will
sometimes recover and run very well sometimes after I
run over bumps in the road. It's happened enough times
now to where I'm fairly sure it's not just my
imagination or coincidence. Of course,there's a few
things that could react to jarring. But I could kinda
visualize that brick bouncing around.
I'm gonna go see what kind of MAP reading I get from
my scanner........
Steve P.
--- "Bernd D. Ratsch" <bernd@dodgetrucks.org> wrote:
>
>
> Easy way to tell on a bad MAP: "Baro" reading on the
> scanner. It should be
> close to what your actual barometric pressure is -
> you can easily check that
> with a weather website in your area. Normally, 29.0
> - 29.5 is the norm with
> 30" during a storm (high/low pressure changes). If
> it's at 31" or
> 27"...something is wrong with the sensor.
>
> The sound you described also strikes a flag - what's
> the engine vacuum at
> idle, 1500rpm, normal cruising, and at WOT? Reason
> for asking is you can
> tell if a cat is plugged up by checking the vacuum.
> If it's plugged up, the
> vacuum under WOT will not go down to "0" and will
> rise slowly but steadily
> (WOT run on the Highway or lonesome street is a goot
> area to test this).
>
> Does your Elmscanner allow for saving data log files
> (Sensor data) and if it
> does, can it be saved into a standard file to
> read/email?
>
> - Bernd
>
>
>
> -----Original Message-----
> From: Steve Preston [mailto:steveophonic@yahoo.com]
> Sent: Saturday, July 21, 2007 8:36 PM
> To: dakota-truck@dakota-truck.net
> Subject: DML: Was checking transmission line
> pressure,now other stuff.
> (Bernd)
>
>
> TPS is rock solid. I checked it with an ohmmeter
> first,then double-checked with the Elmscan when I
> got
> it. Couldn't duplicate a bad spot or a jump in
> resistance in the wrong direction at all. Smooth.
>
> The MAP is a possibility. I don't remember seeing a
> reading from it.
>
> The other day,I slid the rear slider open and
> listened
> to the engine while I drove up a steep hill,and
> swore
> I heard it sputter,but the sound of the exhaust is
> bad
> anyway. It has like a "listening through a tin can"
> sound. There is no rattling like the brick loose or
> anything,but the tone of the exhaust just has a
> metallic,hollow sound. My own 3.9 Dak I used to have
> never sounded like that,I don't think.
>
> I probably need to see what's going on with the
> engine
> vacuum. I have a new digital manometer for HVAC
> use,maybe that'll work. Reads in inches of water
> column. Wish it was analog though.
>
>
> I'll try to pick off your list of suspects one by
> one,Bernd. Thanks!
>
> Steve P.
>
> --- "Bernd D. Ratsch" <bernd@dodgetrucks.org> wrote:
>
> >
> > TPS can also cause the erratic shift...normally
> only
> > at light throttle
> > cruising speeds but it can cause problem shifts if
> > there's a "dead spot" in
> > the TPS circuit. If you have an analog volt meter
> > (simple needle on a
> > gauge) you can measure the TPS and watch the
> > "sweep". Connect the + side of
> > the meter to the TPS signal (back probe the
> sensor)
> > and the - side to
> > ground. Key ON/Engine OFF, move the throttle and
> > watch the needle (it will
> > go from about .5v to 4v as you move the throttle).
> >
> > Things that can cause erratic shift (electronics
> > wise): TPS, Governor
> > Pressure Solenoid, TCC Solenoid, Pressure
> > Transducer. Erratic surging: IAC,
> > TPS, MAP, actual tune of the engine (plugs, wires,
> > cap, rotor)...so if you
> > check all the basics first - you'll narrow it down
> > rather quickly.
> >
> > - Bernd
> >
> > -----Original Message-----
> > From: Steve Preston
> [mailto:steveophonic@yahoo.com]
> > Sent: Saturday, July 21, 2007 8:57 AM
> > To: dakota-truck@dakota-truck.net
> > Subject: Re: DML: RE: Checking transmission line
> > pressure
> >
> >
> > Thanks for the reply,Bernd!
> >
> > I don't have anything to read any transmission
> > sensors
> > with. My Elmscan 5 will do the engine sensors
> > (only,apparently). About all I can do is measure
> > actual fluid pressure with a gauge and look at my
> > speedometer.
> >
> > I'm a little concerned that I can't find anyone on
> > the
> > internet that has had either the sensor or the
> > solenoid cause erratic surging and intermittent
> > performance. All I can find is complaints of
> second
> > gear starts and failure to upshift. Maybe I need
> to
> > verify that the fuel system and the engine vacuum
> is
> > not causing anything before I blame the
> transmission
> > for causing that one symptom for sure.
> >
> > Steve P.
> >
> >
> >
> >
> >
> > --- "Bernd D. Ratsch" <bernd@dodgetrucks.org>
> wrote:
> >
> > >
> > > You can look at the pulse-width of the sensor
> and
> > > line pressure. If the
> > > sensor isn't showing 1psi per mph from 0-30mph,
> > it's
> > > bad (very common
> > > problem). As for using the HVAC gauge, I
> wouldn't
> > > run ATF through that
> > > gauge. You can use a fuel pressure gauge
> > (0-100psi)
> > > and use the line taps
> > > on the side of the transmission.
> > >
> > > - Bernd
> > >
> > > -----Original Message-----
> > > From: Steve Preston
> > [mailto:steveophonic@yahoo.com]
> > > Sent: Friday, July 20, 2007 8:37 PM
> > > To: dakota-truck@dakota-truck.net
> > > Subject: DML: Checking transmission line
> pressure
> > >
> > >
> > > Sup!
> > >
> > > I need to determine which is bad: the governor
> > > pressure sensor,or the solenoid. I'd hate to
> spend
> > > the
> > > considerable sum for a part that I don't need,if
> > > only
> > > one of them is bad. I've read that if the line
> > > pressure doesn't equate to 1 psi per mph as I
> > > drive,the transducer is bad,and if the pressure
> is
> > > right,the sensor is causing the problem. This is
> > on
> > > my
> > > work truck (2003 3.9 CC 42RE)
> > > that runs crappy (feels like engine miss and
> > doesn't
> > > want to upshift unless I back off the gas.) I
> > spent
> > > this afternoon checking the ignition system,and
> > I'm
> > > fairly sure the engine isn't causing it.
> > >
> > > First off,what's a wet gauge? I assume it
> measures
> > > transmission fluid pressure? Does anyone know
> if
> > an
> > > HVAC suction side pressure gauge would work?
>
=== message truncated ===
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This archive was generated by hypermail 2b29 : Wed Aug 01 2007 - 00:15:21 EDT